Distribution,provenance and changes in the past 20 years of organic carbon in the surficial sediments in Hangzhou Bay
Based on the sampling and labortary testing in the summer of 2002,2008,2012,2017 and 2022,the distribution pattern,provenance and changes in the past 20 years of organic carbon of the surface sediments in Hangzhou Bay were discussed.The results showed that the average total organic carbon(TOC)content of 2002,2008,2012,2017 and 2022 were 0.55%、0.50%、0.44%、0.53%和0.51%,respectively,higher in the north Jinshan-Nanhui tidal trough(＞0.6%)and south Zhenhai and Cixi offshore muddy areas(＞0.5%)and lower in west sandy(＜0.4%)and the east region(0.4%～0.5%)of the bay.Correlations between TOC and grain size and Eh indicate that hydrodynamically driven sediment differentiation and redox environment exert a significant control on the transport and accumulation of sedimentary organic carbon in Hangzhou Bay,with its preferential deposition in the fine-grained sediments.Statistical analysis of five periods of TOC in four areas showed obvious decrease and then increase in the northern area,increased over 2002 to 2017,then reduced in the southern and eastern areas and no clear change in the western area.related to potential effects of the declining sediment and organic matter loads caused by natural conditions change and anthropic influences.The C/N、δ13C characteristics of the sediment showed that terrestrial contribution of the TOC was 30%～70%,vared widely in different areas in Hangzhou Bay,with more land sources which were mainly carried by Changjiang River suspended sediments in the northern and south-eastern areas,while more marine origin in the central and eastern areas of the bay.
surficial sedimentsorganic carbonprovenanceHangzhou Bay
万方数据
维普
